Polyimide film with excellent heat resistance and mechanical properties and preparation method thereof
Polyimide films without p-phenylenediamine were prepared by copolymerizing pyromellitic dianhydride with 4,4'-diaminodiphenyl ether and meta-toluidine, solving the problems of foaming and gelation, improving productivity and heat resistance, and making them suitable for applications such as display elements.
Patent Information
- Application Number
- CN202480054427.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-31
- Filing Date
- 2024-08-22
- Publication Date
- 2026-03-24
AI Technical Summary
Existing polyimide films use p-phenylenediamine (PPD) in their preparation process, which leads to foaming and gel formation, resulting in low productivity and process efficiency, and poor chemical resistance at low coefficients of thermal expansion.
Polyimide films without PPD were prepared by copolymerizing pyromellitic dianhydride (PMDA) with 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD). The coefficient of thermal expansion and mechanical properties were improved by block copolymerization.
This technology enables polyimide films to exhibit excellent heat resistance, mechanical properties, and productivity without the use of PPD, making them suitable for applications such as display components.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a polyimide film having excellent heat resistance and mechanical properties and a method for preparing the same. In particular, the present application relates to a polyimide film having excellent heat resistance and mechanical properties without using p-phenylenediamine (PPD) and a method for preparing the same. BACKGROUND
[0002] Polyimide (PI) is a polymer material based on an imide ring, which has excellent chemical stability and a rigid aromatic main chain, and has the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials.
[0003] In general, a polyimide (PI) film is a film made of a polyimide resin, which is a high heat-resistant resin obtained by preparing a polyamic acid derivative through solution polymerization of aromatic diacyl and aromatic diamine or aromatic diisocyanate, and then performing an imidization reaction by closed-loop dehydration at a high temperature.
[0004] Existing polyimide resins mainly use p-phenylenediamine (PPD) as an aromatic diamine, but PPD causes bubbling and gel formation during film preparation, resulting in low productivity and process efficiency. In addition, when a low coefficient of thermal expansion is required, there are problems such as poor chemical resistance despite the use of a large amount of PPD.
[0005] Therefore, there is a need to develop a polyimide film having excellent heat resistance and mechanical properties after an imidization reaction even without using p-phenylenediamine. SUMMARY TECHNICAL PROBLEM
[0006] An object of the present application is to provide a polyimide film having excellent heat resistance and mechanical properties after an imidization reaction without using p-phenylenediamine (PPD) and a method for preparing the same.
[0007] In addition, another object of the present application is to provide a display element including the above-described polyimide film. TECHNICAL SOLUTION
[0008] Various modifications can be made in the present application and various embodiments can be implemented. Therefore, hereinafter, a specific embodiment will be described in detail. However, this is not intended to limit the present application to a specific embodiment, but to cover all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present application.
[0009] The terminology used in this application is for describing particular embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, and should not be construed as excluding the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof.
[0010] When content, concentration, or other values or parameters are given in this document as an enumeration of ranges, preferred ranges, or preferred upper and lower limits, it should be understood that all ranges consisting of any pair of preferred upper and lower limits are specifically disclosed, regardless of whether the range is disclosed individually.
[0011] Unless otherwise stated, the ranges of values mentioned in this document are not limited to the specific values mentioned when the range was defined.
[0012] As used herein, “dianhydride” is intended to include its precursors or derivatives, and may also be referred to as “dianhydride acid,” “dianhydride,” or “acid dianhydride.” These precursors or derivatives may not technically be dianhydrides, but can still react with diamines to produce polyamic acid, and polyamic acid can be converted back to polyimide.
[0013] As used herein, “diamine” is intended to include its precursors or derivatives, which may not technically be diamines but can still react with dianhydrides to form polyamic acids, and polyamic acids can be converted back into polyimides.
[0014] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted as having an idealized or overly formal meaning unless expressly defined in this application. Specific details of implementing the invention will now be described.
[0015] This invention relates to a polyimide film with excellent heat resistance and mechanical properties, and a method for preparing the same.
[0016] polyimide film
[0017] This invention provides a polyimide film comprising a copolymer obtained by copolymerizing a dianhydride monomer comprising pyromellitic dianhydride (PMDA) with a diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD), wherein the film has a coefficient of thermal expansion (CTE) in the transverse (TD) direction, measured at a temperature range of 50°C to 200°C and a heating rate of 10°C / min, from -5 ppm / °C to 2.5 ppm / °C. TD ), and a modulus of 8 GPa or above.
[0018] Specifically, the polyimide film may have a coefficient of thermal expansion (CTE) in the transverse direction (TD) of -5 ppm / °C to 2.5 ppm / °C, preferably -4.5 ppm / °C to 1.5 ppm / °C, measured in a temperature range of 50°C to 200°C and a heating rate of 10°C / min. TD ).
[0019] Specifically, the polyimide film may have a modulus of 8 GPa or higher. For example, the lower limit of the modulus may be 9 GPa or higher, 9.5 GPa or higher, or 10 GPa or higher. Furthermore, the upper limit of the modulus is not specifically limited and may be 18 GPa or lower, 17 GPa or lower, 16 GPa or lower, or 15 GPa or lower. The modulus can be measured using an Instron 5564 UTM instrument from INSTRON at a rate of 20 mm / min by preparing samples with a length of 80 mm and a width of 15 mm, and the average value of 10 samples is calculated.
[0020] In polyimide films, the coefficient of thermal expansion (CTE) along the longitudinal direction (MD) is... MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD The difference between (CTE) MD -CTE TD The temperature can be -3ppm / °C to 3ppm / °C, preferably -2ppm / °C to 2ppm / °C, and more preferably -1.8ppm / °C to 1.8ppm / °C.
[0021] The average coefficient of thermal expansion (CTE) of polyimide films Ave The coefficient of thermal expansion (CTE) can range from -4.25 ppm / °C to 3.0 ppm / °C, preferably from -4.35 ppm / °C to 2.0 ppm / °C. Ave The coefficient of thermal expansion (CTE) of the polyimide film in the longitudinal direction (MD) can be... MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TDThe average value of ).
[0022] Coefficient of thermal expansion (CTE) in the longitudinal direction (MD) MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD The slope can be determined by measuring the slope at 50 mN at a rate of 10°C / min in the range of 50°C to 200°C using a TA TMA instrument (Q400).
[0023] Polyimide films may have a glass transition temperature (Tg) of 380°C or higher. For example, the lower limit of the glass transition temperature may be 385°C or higher, 395°C or higher, or 398°C or higher. Furthermore, the upper limit of the glass transition temperature is not specifically limited, but may be 500°C or lower, 495°C or lower, or 490°C or lower. The glass transition temperature is measured using a dynamic mechanical analyzer (DMA) at a heating rate of 10°C / min.
[0024] The polyimide film may have a thickness-based chemical resistance of -25% to -13%, preferably -24.5% to -13.5%.
[0025] In one embodiment, the polyimide film may have a weight-based chemical resistance of -25% to -10%, preferably -23.5% to -11%.
[0026] The aforementioned thickness-based chemical resistance and weight-based chemical resistance were measured according to ASTM D570 absorption rate, respectively. Regarding immersion and storage criteria in solution, chemical resistance was measured by examining the changes in weight and thickness after immersion in a 15% NaOH solution and storage at 60°C for 30 minutes.
[0027] The polyimide film may have a hygroscopic expansion coefficient (CHE) of 3 ppm / RH% to 6 ppm / RH%, preferably 3.5 ppm / RH% to 5 ppm / RH%. The hygroscopic expansion coefficient can be measured using a PMIC device by stabilizing the film under humidity conditions ranging from 3%RH to 90%RH until no dimensional change occurs.
[0028] The thickness of the polyimide film can be appropriately selected considering the application of the polyimide film, its operating environment, and physical properties. For example, polyimide films can have thicknesses of 1 μm to 100 μm, 15 μm to 70 μm, 25 μm to 50 μm, or 30 μm to 45 μm, but are not limited to these.
[0029] Another embodiment of the present invention provides a multilayer film comprising a polyimide film and a thermoplastic resin layer.
[0030] Another embodiment of the present invention provides a flexible metal foil laminate comprising a polyimide film and a conductive metal foil.
[0031] Another embodiment of the present invention provides an electronic component comprising a flexible metal foil laminate.
[0032] Another embodiment of the present invention provides a display element comprising a polyimide film.
[0033] copolymer
[0034] The copolymers described above are obtained by copolymerizing a dianhydride monomer including pyromellitic dianhydride (PMDA) with a diamine monomer including 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD).
[0035] The copolymer can be a block copolymer having two or more blocks.
[0036] The block copolymer consists of the following: a first block obtained by copolymerizing a dianhydride monomer composed of pyromellitic dianhydride (PMDA) with a diamine monomer composed of meta-toluidine (m-TD); and a second block obtained by copolymerizing a dianhydride monomer composed of pyromellitic dianhydride (PMDA) with a diamine monomer composed of 4,4'-diaminodiphenyl ether (ODA).
[0037] The content of meta-toluidine (m-TD) in the total diamine monomer of the copolymer is 40 mol% to 80 mol%, preferably 45 mol% to 75 mol%, more preferably 50 mol% to 70 mol%, and even more preferably 55 mol% to 65 mol%. When the content of meta-toluidine is less than 40 mol%, it is not preferred because the polyimide film has poor hygroscopicity, low dielectric properties, and extremely low chemical resistance. When the content of meta-toluidine exceeds 80 mol%, it is not preferred because it is difficult to form a polyimide film.
[0038] The content of 4,4'-diaminodiphenyl ether (ODA) in the total diamine monomer of the copolymer is 20 mol% to 60 mol%, preferably 25 mol% to 55 mol%, more preferably 30 mol% to 50 mol%, and even more preferably 35 mol% to 45 mol%. When the amount of 4,4'-diaminodiphenyl ether is less than 20 mol%, it is difficult to subsequently form a polyimide film, and therefore it is not preferred. When it exceeds 60 mol%, the low hygroscopicity and low dielectric properties caused by meta-toluidine are not significant, and therefore it is not preferred.
[0039] The molar ratio of dianhydride monomer to diamine monomer can be 1:2 to 2:1, preferably 1:1.
[0040] The copolymer may include a diamine monomer in a content of 90 mol% to 110 mol%, preferably 95 mol% to 105 mol%, more preferably 98 mol% to 102 mol%, or even more preferably 99 mol% to 101 mol%.
[0041] The copolymer may include dianhydride monomers in a content of 90 mol% to 110 mol%, preferably 95 mol% to 105 mol%, more preferably 98 mol% to 102 mol%, or even more preferably 100 mol%.
[0042] Based on 100 mol% of the diamine monomer, the copolymer may include 95 mol% to 105 mol% of the dianhydride monomer. For example, the lower limit of the dianhydride monomer may be 95.5 mol% or more, 96 mol% or more, 96.5 mol% or more, 97 mol% or more, 97.5 mol% or more, 98 mol% or more, 98.5 mol% or more, 99 mol% or more, or 99.5 mol% or more, and its upper limit may be 105 mol% or less, 104 mol% or less, 103 mol% or less, 102 mol% or less, 101 mol% or less, or 100 mol% or less.
[0043] Method for preparing polyimide films
[0044] This invention provides a method for preparing a polyimide film, comprising: copolymerizing a dianhydride monomer comprising pyromellitic dianhydride (PMDA) with a diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD), wherein the polyimide film has a coefficient of thermal expansion (CTE) in the transverse (TD) direction, measured at a temperature range of 50°C to 200°C and a heating rate of 10°C / min, from -5 ppm / °C to 2.5 ppm / °C. TD ), and the modulus of the polyimide film is 8 GPa or above.
[0045] Specifically, the polyimide film may have a coefficient of thermal expansion (CTE) in the transverse direction (TD) of -5 ppm / °C to 2.5 ppm / °C, preferably -4.5 ppm / °C to 1.5 ppm / °C, measured in a temperature range of 50°C to 200°C and a heating rate of 10°C / min. TD ).
[0046] Specifically, the polyimide film can have a modulus of 8 GPa or higher. For example, the lower limit of the modulus can be 9 GPa or higher, 9.5 GPa or higher, or 10 GPa or higher. Furthermore, the upper limit of the modulus is not specifically limited, but can be 18 GPa or lower, 17 GPa or lower, 16 GPa or lower, or 15 GPa or lower. The modulus can be measured using an Instron 5564 UTM instrument from INSTRON at a rate of 20 mm / min by preparing samples with a length of 80 mm and a width of 15 mm, and the average value of 10 samples is calculated.
[0047] The copolymerization step described above may include: preparing a first block by copolymerizing a dianhydride monomer comprising pyromellitic dianhydride (PMDA) with a diamine monomer comprising meta-toluidine (m-TD); and preparing a second block by copolymerizing a dianhydride monomer comprising pyromellitic dianhydride (PMDA) with a diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA).
[0048] In the preparation of the first block, the content of the diamine monomer including meta-toluidine (m-TD) can be greater than the content of the dianhydride monomer including pyromellitic dianhydride (PMDA).
[0049] Specifically, in the preparation of the first block, the content of the diamine monomer including m-toluidine (m-TD) can be from 40 mol% to 80 mol%, the content of the dianhydride monomer including pyromellitic dianhydride (PMDA) can be from 20 mol% to 70 mol%, and the content of the diamine monomer including m-toluidine (m-TD) (M m-TD ) and the content of dianhydride monomers including pyromellitic dianhydride (PMDA) (M 1st PMDA The ratio of (M) m-TD / M 1st PMDA () can be greater than 1 and less than 2.
[0050] When the ratio (M) m-TD / M 1st PMDA When the value is 1 or less or 2 or more, it is not preferred because it is difficult to form a block copolymer with the desired form.
[0051] In the preparation of the second block, the content of the diamine monomer including 4,4'-diaminodiphenyl ether (ODA) can be less than the content of the dianhydride monomer including pyromellitic dianhydride (PMDA).
[0052] Specifically, in the preparation of the second block, the content of the diamine monomer including 4,4'-diaminodiphenyl ether (ODA) can be from 20 mol% to 60 mol%, the content of the dianhydride monomer including pyromellitic dianhydride (PMDA) can be from 30 mol% to 80 mol%, and the content of the diamine monomer including 4,4'-diaminodiphenyl ether (ODA) (M ODA ) and the content of dianhydride monomers including pyromellitic dianhydride (PMDA) (M 2nd PMDA The ratio of (M) ODA / M 2nd PMDA () can be greater than 0 and less than 1.
[0053] When the ratio (M) ODA / M 2nd PMDA When the value is 0 or 1 or higher, it is not preferred because it is difficult to form a block copolymer with the desired form.
[0054] The first and second blocks can each be prepared in the presence of a solvent.
[0055] The solvent may include at least one selected from the group consisting of N,N'-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), diethylacetamide (DEAc), N-ethyl-2-pyrrolidone (NEP), N,N'-diethylformamide (DEF), dimethylpropionamide (DMPA), and γ-butyrolactone (GBL), preferably N,N'-dimethylformamide (DMF).
[0056] Another embodiment of the present invention provides a multilayer film comprising a polyimide film prepared by the method described above for preparing a polyimide film and a thermoplastic resin layer.
[0057] Another embodiment of the present invention provides a flexible metal foil laminate comprising a polyimide film prepared by the method described above for preparing a polyimide film and a conductive metal foil.
[0058] Another embodiment of the present invention provides an electronic component comprising a flexible metal foil laminate as described above.
[0059] Another embodiment of the present invention provides a display element comprising the polyimide film as described above.
[0060] Beneficial effects
[0061] The polyimide film and its preparation method according to the present invention do not use p-phenylenediamine (PPD), thus making them relatively competitively priced and offering excellent productivity and process efficiency.
[0062] Furthermore, the polyimide film according to the present invention has excellent heat resistance and mechanical properties.
[0063] Furthermore, the polyimide film according to the present invention can be applied to display elements. Detailed Implementation
[0064] To facilitate understanding of the present invention, some embodiments are listed below. These embodiments are only used to facilitate a better understanding of the present invention, but the scope of the present invention is not limited by these embodiments.
[0065] <Example>
[0066] Example 1. Preparation of polyimide film
[0067] Example 1-1
[0068] A solution containing a first block (m-TD / PMDA block) was prepared by mixing and polymerizing 80 mol% of meta-toluidine (m-TD) as a diamine monomer with 60 mol% of pyromellitic dianhydride (PMDA) as a dianhydride monomer in 100 mol% dimethylformamide (DMF).
[0069] In the solution prepared above, 20 mol% of 4,4'-diaminodiphenyl ether (ODA) as a diamine monomer and 37 mol% of pyromellitic dianhydride (PMDA) as a dianhydride monomer are mixed and polymerized to generate a second block (ODA / PMDA block).
[0070] Finally, a polyamic acid comprising a first block (m-TD / PMDA block) and a second block (ODA / PMDA block) was prepared by adding 3 mol% PMDA.
[0071] After mixing polyamic acid with a catalyst, the degassed polyamic acid was coated onto a glass plate. Then, using an applicator, the mixture was uniformly coated onto the glass plate surface according to a calculated solvent-to-solid ratio. The mixture was then cured under a nitrogen atmosphere at temperatures ranging from 130°C (4 minutes) to 280°C (4 minutes) to 420°C (4 minutes) to obtain a polyimide film. At this point, the film thickness was 33.5 μm.
[0072] Examples 1-2 to 1-6
[0073] Except for adjusting the ratio of m-toluidine, ODA, and PMDA as shown in Table 1 below, the polyimide film was prepared in the same manner as in Example 1-1.
[0074] Comparative Example 1-1
[0075] Except for adjusting the ratio of m-toluidine, ODA and PMDA as shown in Table 1 below, the polyimide film was prepared in the same manner as in Example 1-1.
[0076] Comparative Examples 1-2
[0077] Random copolymerized polyimide films were prepared by mixing 50 mol% meta-toluidine (m-TD) and 50 mol% 4,4'-diaminodiphenyl ether (ODA) with 97 mol% dianhydride compound, pyromellitic dianhydride (PMDA), in 100 mol% dimethylformamide (DMF), followed by the addition of 3 mol% PMDA.
[0078] Table 1 below shows the composition and content of diacyl monomers and diamine monomers used to prepare polyimide films according to Examples 1-1 to 1-6 and Comparative Example 1-1.
[0079] [Table 1]
[0080] Table 2 below shows the composition and content of dianhydride monomers and diamine monomers used to prepare polyimide films according to Comparative Examples 1-2.
[0081] [Table 2]
[0082] <Experimental Example>
[0083] Experimental Example 1. Evaluation of the physical properties of polyimide films
[0084] (1) Coefficient of thermal expansion (CTE)
[0085] For the polyimide films of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2, the slopes in the longitudinal (MD) and transverse (TD) directions were measured using a TA TMA instrument (Q400) at 10°C / min and 50 mN, respectively, within the range of 50°C to 200°C. The coefficient of thermal expansion (CTE) in the longitudinal (MD) direction was then determined. MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD Calculate the average coefficient of thermal expansion (CTE). Ave ) and the coefficient of thermal expansion in the longitudinal direction (MD) (CTE) MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD The difference between (CTE) MD -CTE TD The coefficient of thermal expansion (CTE) of polyimide film in the longitudinal direction (MD) MD ), and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD), average thermal expansion coefficient (CTE) Ave ), and the coefficient of thermal expansion in the longitudinal direction (MD) (CTE) MD ) and the coefficient of thermal expansion in the transverse direction (TD) (CTE) TD The difference between (CTE) MD -CTE TD The corresponding measurement results are shown in Table 3 below.
[0086] (2) Glass transition temperature (Tg)
[0087] For the polyimide films of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2, the glass transition temperature was measured using DMA at 10°C / min. The results are shown in Table 3.
[0088] (3) Modulus
[0089] For the polyimide films of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2, samples with a length of 80 mm and a width of 15 mm were prepared. The modulus of the samples was measured at a rate of 20 mm / min using an Instron 5564 UTM instrument from INSTRON Corporation, and the average value of 10 samples was calculated. The results are shown in Table 3 below.
[0090] (4) Chemical resistance
[0091] For the polyimide films of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2, chemical resistance based on thickness and chemical resistance based on weight were measured, and the results are shown in Table 3 below.
[0092] The aforementioned thickness-based chemical resistance and weight-based chemical resistance were measured according to ASTM D570 absorption rate, respectively. Regarding immersion and storage criteria in solution, chemical resistance was measured by examining the changes in weight and thickness after immersion in a 15% NaOH solution and storage at 60°C for 30 minutes.
[0093] (5) Hygroscopic expansion coefficient (CHE)
[0094] Regarding the polyimide films of Examples 1-2, 1-3, 1-5 and Comparative Examples 1-1 and 1-2 above, the coefficient of hygroscopic expansion was measured by stabilizing them at 3%RH to 90%RH until no dimensional change occurred using a PMIC device. The results are shown in Table 3.
[0095] Table 3 below summarizes the physical property evaluation results of the polyimide films of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2.
[0096] [Table 3]
[0097] According to Table 3, when block copolymers are included, the examples with m-TD contents of 40 to 80 mol% exhibit excellent chemical resistance compared to Comparative Example 1-1 with 30 mol% m-TD content, and also show better CTE and CHE.
[0098] Furthermore, when comparing the physical properties with and without blocks at the same content (Examples 1-5 and Comparative Examples 1-2), although other physical properties are similar, it can be found that the heat resistance and chemical resistance are significantly superior when blocks are included.
[0099] These results demonstrate that the polyamic acid of the present invention and the polyimide film prepared therefrom exhibit excellent heat resistance, chemical resistance, moisture resistance and mechanical properties without the use of p-phenylenediamine (PPD).
[0100] Furthermore, the polyimide film according to the present invention does not use p-phenylenediamine (PPD), thus it is relatively competitively priced and has excellent productivity and process efficiency.
[0101] In this specification, detailed descriptions of content that can be fully understood and inferred by those skilled in the art have been omitted, and many variations and modifications may be made without altering the technical spirit or essential configuration of the invention, except for the specific exemplary embodiments described herein. Therefore, the invention may also be practiced in ways other than those specifically described and illustrated herein, as will be apparent to those skilled in the art.
Claims
1. A polyimide film, characterized in that, include: The copolymer is obtained by copolymerizing a dianhydride monomer including pyromellitic dianhydride (PMDA) with a diamine monomer including 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD). The membrane described herein has a coefficient of thermal expansion (CTE) in the transverse (TD) direction, measured at a temperature range of 50°C to 200°C and a heating rate of 10°C / min, ranging from -5 ppm / °C to 2.5 ppm / °C. TD ),as well as Modulus of 8 GPa or above.
2. The polyimide film according to claim 1, characterized in that, In the polyimide film, the coefficient of thermal expansion (CTE) in the longitudinal direction (MD) is... MD ) and the coefficient of thermal expansion (CTE) in the transverse (TD) direction. TD The difference between (CTE) MD -CTE TD The temperature range is -3 ppm / °C to 3 ppm / °C.
3. The polyimide film according to claim 1, characterized in that, The average coefficient of thermal expansion (CTE) of the polyimide film Ave The concentration ranges from -4.25 ppm / °C to 3.0 ppm / °C, and... The average coefficient of thermal expansion (CTE) Ave The coefficient of thermal expansion (CTE) of the polyimide film in the longitudinal direction (MD) is... MD ) and the coefficient of thermal expansion (CTE) in the transverse (TD) direction. TD The average value of ).
4. The polyimide film according to claim 1, characterized in that, The copolymer is a block copolymer having two or more blocks.
5. The polyimide film according to claim 4, characterized in that, The block copolymer is composed of or includes: The first block is obtained by copolymerization of a dianhydride monomer composed of pyromellitic dianhydride (PMDA) and a diamine monomer composed of meta-toluidine (m-TD); and The second block is obtained by copolymerizing a dianhydride monomer composed of pyromellitic dianhydride (PMDA) with a diamine monomer composed of 4,4'-diaminodiphenyl ether (ODA).
6. The polyimide film according to claim 1, characterized in that, The content of meta-toluidine (m-TD) in the total diamine monomer of the copolymer is from 40 mol% to 80 mol%.
7. The polyimide film according to claim 1, characterized in that, The content of 4,4'-diaminodiphenyl ether (ODA) in the total diamine monomer of the copolymer is from 20 mol% to 60 mol%.
8. The polyimide film according to claim 1, characterized in that, The polyimide film has a glass transition temperature (Tg) of 380°C or higher.
9. The polyimide film according to claim 1, characterized in that, The polyimide film has a thickness-based chemical resistance of -25% to -13% and a weight-based chemical resistance of -25% to -10%.
10. The polyimide film according to claim 1, characterized in that, The polyimide film has a hygroscopic expansion coefficient of 3ppm / RH% to 6ppm / RH.
11. The polyimide film according to claim 1, characterized in that, The thickness of the polyimide film is from 1 μm to 100 μm.
12. A method for preparing a polyimide film, characterized in that, include: The dianhydride monomer, including pyromellitic dianhydride (PMDA), is copolymerized with diamine monomers including 4,4'-diaminodiphenyl ether (ODA) and meta-toluidine (m-TD). The polyimide film described herein has a coefficient of thermal expansion (CTE) in the transverse direction (TD) of -5 ppm / °C to 2.5 ppm / °C at a temperature range of 50°C to 200°C and a heating rate of 10°C / min. TD ),as well as The modulus of the polyimide film is 8 GPa or higher.
13. The method according to claim 12, characterized in that, The copolymerization includes: The first block was prepared by copolymerizing a dianhydride monomer including pyromellitic dianhydride (PMDA) with a diamine monomer including meta-toluidine (m-TD); and The second block was prepared by copolymerizing a dianhydride monomer including pyromellitic dianhydride (PMDA) with a diamine monomer including 4,4'-diaminodiphenyl ether (ODA).
14. The method according to claim 13, characterized in that, In the preparation of the first block The content of the diamine monomer comprising the meta-toluidine (m-TD) is from 40 mol% to 80 mol%. The content of the dianhydride monomer, including the pyromellitic dianhydride (PMDA), is from 20 mol% to 70 mol%. The content (M) of the diamine monomer including the meta-toluidine (m-TD) m-TD The content of dianhydride monomers including the pyromellitic dianhydride (PMDA) (M) 1st PMDA The ratio of (M) m-TD / M 1st PMDA () Greater than 1 and less than 2.
15. The method according to claim 13, characterized in that, In the preparation of the second block The content of the diamine monomer comprising the 4,4'-diaminodiphenyl ether (ODA) is from 20 mol% to 60 mol%. The content of the dianhydride monomer, including the pyromellitic dianhydride (PMDA), is from 30 mol% to 80 mol%. The diamine monomer (M) including the 4,4'-diaminodiphenyl ether (ODA) ODA The content of ) and the dianhydride monomer (M) including the pyromellitic dianhydride (PMDA) 2nd PMDA The ratio of the content of ) (M) ODA / M 2nd PMDA () is greater than 0 and less than 1.